Dishwashing machine



y 62 R. L. BUTSCH ET AL 3,034,518

DISHWASHING MACHINE Filed March 22, 1961 2 Sheets-Sheet 1 .L as r 33 RICHARD L. BUTSCH J'OHANN F. SCHULTE.

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THEIR ATTORNEY y 1962 R. L. BUTSCH ET AL 3,034,518

DISHWASI-IING MACHINE 2 Sheets-Sheet 2 Filed March 22, 1961 F'IG.2

THEIR ATTORNEY United States Patent 3,034,518 DISHWASHING MACHINE Richard L. Butsch, Jeifersontown, and Johann F. Schulte,

Valley Station, Ky., assignors to General Electric Company, a corporation of New York Filed Mar. 22, 1961, Ser. No. 97,593 6 Claims. (Cl. 134-58) This invention relates to washing machines, and more particularly to a machine for washing dishes and disposing of the food residue which may be present on such dishes when they are put in the machine. This is a continuationin-part of our application Serial No. 33,428, filed on June 2, 1960, now abandoned.

At the present time, many commercially available dishwashing machines effectthe washing action on the dishes by water forced from a circulating system by a pump. During at least part of the conventional dishwashing cycle, the water so circulated is, after it falls to the bottom of the compartment in which the dishes are located, then recirculated by the pump back to the circulating means. The main function of the water circulated in the compartment, at least during the initial part of a dishwashing operation, is to pick up food residue, either present on the dishes in the compartment, or fallen from the dishes and lying at the bottom of the compartment. For this initial removal of foods to be effective, a high rate of water circulation is necessary, and in order to achieve this high rate of water circulation without consumption of an undue quantity of water, the recirculation described above must be provided. This, however, introduces the problem that the food residue, unless filtered out in some way, may be recirculated back into the compartment with the water; recirculation of the residue is, of course, undesirable since the food may then be redeposited on the dishes and the washing action to follow will not be as effective, or in fact, the food may actually foul the recirculation system.

It is an object of our invention to provide structure for permitting recirculation of water at a high rate with only a minor loss of the water used, while at the same time causing the removal of the food through a drain so that it will not be recirculated.

Briefly stated, in accordance with one aspect of our invention, we provide a dishwasher which has a compartment for receiving dishes to be washed by the action of liquid circulating means which forcibly circulates liquid in the compartment. The bottom of the compartment communicates with the top of a drain passage, sloping downwardly from its edges toward the passage, and a liquid receptacle or sump is positioned below the compartment bottom about the drain passage. The drain passage includes suitable means controlling removal of solids and liquids from the passage. For instance, this means may take the form of an electrical device having two conditions (energized and deenergized); in one condition, it causes removal of solids and liquids, and in its other condition it prevents the removal of solids and liquids. in order to permit the liquid from the compartment to enter the receptacle, the compartment bottom above the receptacle and about the drain passage is formed as a foraminous member so as to prevent solids from passing into the receptacle but permit liquid to pass back thereinto. This liquid is then recirculated by suitable high flow capacity pumping means having an inlet connected to the receptacle adjacent the bottom thereof and having an outlet connected to the circulating means.

Liquid may be provided to the machine through an inlet passage which, in the preferred form of our invention, performs also the function of a vent, having an upper end open to atmosphere and a lower end communicating directly with the receptacle. This provision of liquid may be controlled by means of an inlet valve in the conventional manner. Low flow capacity means are provided for voiding liquid from the receptacle to the drain passage.

In combination with the foregoing structure, we provide sequence control means which, by its operation, tolls a dishwashing operation. The sequence control means controls, in the usual manner, the various operating components of the machine; in the present case this includes the means controlling the drain passage, the pumping means, and the inlet valve. As an important feature of our invention, our sequence control means correlate the components during an initial rinse step so that the inlet valve is opened for a predetermined period to allow a suitable amount of water into the receptacle, and the passage controlling means causes solids andI liquids to be removed from the drain passage simultaneously with the operation of the pumping means.

It has been found that the high flow rate of the pumping means will cause solids to be washed across the forarninous member to the drain passage together with a small proportion of the total amount of liquid. Therefore, as a result of the simultaneous removal of solids and liquids from the drain passage and the operation of the pumping means, a major part of the liquid passes through the for-aminous member back into the receptacle for recirculation, while a small amount carries the solids over the foraminous member to the drain passage for removal. This simultaneous removal of solids and liquids from the drain passage and recirculation of liquid by the pumping means has been found to be highly effective in providing an efiective self-cleaning structure while limiting the quantity of water required for the rinse step.

The subject matter which we regard as our invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. Our invention, however, both as to organization and method of operation together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings.

In the drawings:

FIGURE 1 is a front elevational view, with some of the parts broken away, of a first embodiment of our improved dishwasher;

FIGURE 2 is a simplified schematic electrical diagram showing a control circuit for the machine of FIGURE 1;

FIGURE 3 is a development of the surfaces of the cams shown in FIGURE 2 thereby showing the sequence of operation of the components illustrated in FIGURES 1 and 2; and

FIGURE 4 is a fragmentary front elevational view showing a second embodiment of our invention.

Referring now to FIGURE 1, there is shown a dishwasher 1 having a closed washing compartment or tub 2 of generally rectangular configuration in which are mounted an upper rack 3 and a lower rack 4 arranged to support dishes or the like during washing operations. The compartment 2 is accessible through any conventional means such as, for instance, by the opening of the lid member '5 pivotable at one end on concealed hinges (not shown). The compartment 2 has a bottom portion 6 which slopes from its edges downwardly toward a drain opening 7. A portion of the compartment bottom 6 around the drain opening 7 is formed as a foraminous member 8, which may be of any conventional type such as a perforated metal plate or a screen, and which is for purposes of illustration shown here as a screen.

Positioned near the bottom of the compartment 2 is a suitable recirculation means 9 formed to circulate liquid within the compartment 2 so as to effect a washing action on dishes located in the compartment. In the emcauses pipe to rotate about its center portion 11 while I at the same time the liquid is forcibly ejected under pres sure from the nozzles 12 into compartment 2. Pump 13 has an inlet 16 which communicates with the bottom 17 of a receptacle 18 positioned below the bottom 6 of the compartment 2 about a drain passage 19 which communicates with opening 7. It will further be noted that the positioning of the receptacle 18 is such that it is directly below the foraminous member 8.

The drain passage 19 leads to a member "20 capable of either removing liquid and food particles from drain passage 19 at a rate sufiicient to prevent the liquid therein from rising substantially within the passage, or alternatively of retaining such matter within the passage 19.

For instance, the preferred form constitutes a food grinding and disposing unit of any conventional design, many food grinding and disposing structures presently being commercially available and being formed so as to pass food and liquid from a drain passage out to a drain pipe 21 or else to retain such matter within the drain passage 19. However, it will be understood that the unit 20 may be provided simply in the form of a valve for retaining the matter within passage 19 or permitting removal therefrom by gravity, provided the present practice of removing the larger insoluble pieces of food residue (such as bones, corn cobs, etc.) be followed.

The drain passage 19 communicates with the receptacle 18 through suitable openings 22 which are preferably formed so that liquid passing down through drain passage 19 will not be likely to be diverted through the openings 22, but so that liquid in receptacle 18 may pass through the openings 22 into the drain passage for removal by unit 20. As an important aspect of our invention, these openings 22 represent a relatively low flow capacity compared to the capacity of the system which includes pump 14. For example, in one practical embodiment of our structure the recirculation system may be capable of recirculating thirty to sixty gallons per minute whereas the capacity of the openings 22 will be on the order of a pint to a quart per minute.

A water inlet conduit 23 has its lower end 24 communicating directly with the interior of receptacle 18, and has its upper end 25 open to atmosphere so as to perform also the function of an air vent. This may be effected in any suitable manner such as, for instance, by providing one or more openings such as 26 in portion 27 of the dishwasher housing so that there is a direct communication between the outside atmosphere and the interior 28 of housing portion 27. A pipe 29 extends down into spaced relation to the upper end 25 of the conduit 23 from a valve 30 controlled by any suitable means such as a solenoid 31. Solenoid 31 in turn is controlled by conventional sequence control means, generally indicated by the numeral '32 and whose function in correlating the operation of the various components will be described in detail herebelow. It will be understood that the sequence control mechanism 32 includes a manually operable member 33 which may be used by an operator so that, by manual operation thereof, a dishwashing operation will be initiated, sequence control mechanism 32 then causing automatically a complete dishwashing operation to be provided and terminated as will be explained herebelow.

Referring now to FIGURE 2 there is shown a highly simplified control circuit suitable for causing an appropriate sequence of steps forming a dishwashing operation. It will be understood that the circuit as shown eliminates a number of conventional interlocks and safety features (such as a lid switch) and other features which conventionally form part of such circuit but which in no way relate to our present invention and therefore, for the sake of clarity, have been eliminated. conventionally,

the various components of machine 1 are energized across the conventional domestically available volt 60 cycle alternating current source of power by conductors 34 and 35.

The assembly 32 shown in FIGURE 1 will normally include a suitable operating motor 36 driving a bank of cams A, B, C, D, and E, the cams in turn controlling timer switches 37, 38, '39, 49 and 41. It will be understood that the motor 36, the cams A-E and the switches 37-41 normally are provided as the unitary assembly 32. Switch 37 is connected in series with motor 36 so as to control the energization of the timer motor across conductors 34 and 35; in similar fashion, switch 38 controls the energization of water valve solenoid 31, switch 39 controls the energization of pump motor 15, and svn'tch 40 controls the energization of the unit 20. The switch 41 has been shown as controlling a suitable resistance heating element 42 which is shown, although not a part of the invention, since it is an integral part of the usual complete dishwasher operation as presently provided by commercially produced machines.

Referring now to FIGURE 3, the developed surfaces of the cams A-E have been shown in order to illustrate the particular correlation of the operation of the components of the machine 1 by the sequence control assembly 32, it being understood that when a cam surface is shown in FIGURE 3 as a line at a higher level it indicates closure of the associated switch and when the line is at a lower level it indicates opening of the associated switch. Briefly, the conventional sequence of steps is followed in that a suitable number of rinse operations (at least one) is provided after each of which rinses the water is drained out. A washing operation is then provided, that water is drained out, and then a suitable number of rinses and drains follow, after which the dishes are dried.

A particular point of importance to our invention arises in the correlation of the components of the machine during the first rinse operation, it being understood that prior to this rinse operationthe dishes have been inserted in the machine in compartment 2 substantially as they came from the table, and that therefore some food residue will be on the dishes and additional food residue will have fallen off the dishes and be lying on the bottom 6 of the compartment 2. To initiate the operation the manually operable member 33 is turned to rotate the cams A-E so that they are moved to the start position for the cycle.

At this point, cam A closes switch 37 to energize the timer motor so that the cams then continue to rotate slowly to control a dish-washing operation without need of further manual operation. At the beginning of the first rinse operation the cam B closes switch 38 to energize solenoid 31 to cause introduction of hot water to the machine from valve 30 through pipe 29, and then down through conduit 23 into receptacle 18. After a suitable water level, which must be below member 8 has been established within the receptacle 18, cams C and D cause switches 39 and 40 to energize motor 15 and unit 20 respectively so that they operate at the same time, i.e., substantially simultaneously. The operation of motor 15 recirculates the liquid in receptacle 18 at a high rate, which as mentioned, may be on the order of sixty gallons per minute. This liquid is thrown up from nozzles 12 into compartment 2 where it knocks the food residue off the dishes and, in descending, also carries the food residue across the compartment bottom 6 over the foraminous member 8 to the drain opening 7; this food residue then passes down through drain passage 19, and because of the operation of unit 29 is carried out through conduit 21.

In this operation, it has been found that a relatively small amount, perhaps on the order of 5% to 10%, of the water thrown up into the compartment 2 passes over the foraminous member 8 to opening 7 and passes down through passage 19 with the solids. The remainder passes through member 8 into the receptacle 18 and, except for a small amount being lost through openings 22, is recirculated by passing through inlet 16 to pump 14 and from pump 14 through outlet 13 to the circulation member 9. Thus, a very high amount of water may be circulated within the compartment 2 while at the same time the solids are being removed from the machine so that they will not foul its operation. All this is done with only a very gradual loss of water. In practice, it has been found that a total of two gallons of water provided during this first rinse operation are sufficient for practical purposes to provide a one minute rinse; it has also been found that a one minute rinse efiects virtually total removal of visible food particles from the dishes and from the bottom 6 of the compartment 2.

It is highly important that the food residue be removed as soon as it passes into drain pasage '19 during this initial rinse operation since, at this time, a very substantial amount of food residue may be present and retention of this solid matter in the drain passage 19 may foul the operation of the machine. By our arrangement, i. e., the cooperative relationship between motor 15 and unit 20, we effect the immediate removal of the food matter while at the same time effecting a very substantial economy in the amount of water being used to wash the food particles down the drain passage 19.

The maximum liquid level in receptacle 18 is retained below the lowest part of the foraminous member 8, this being achieved by suitably proportioning receptacle 18 and timing the water inlet and recirculation operations. It will further be noted that, with the liquid inlet 23 also serving as a connection to atmosphere, there is a connection to atmosphere on the same side of foraminous member 8 as the pump 14. As a result, the suction of pump 14 will never be used to extrude food through the foramina of member 8. The liquid level is never high enough, and if the receptacle 18 should at some time be pumped dry, the suction of the pump will be exerted primarily to pull air into end 25 of conduit 23. Since there is this direct communication between them, there will not be any tendency to extrude any food residue that may be positioned over the foramina of member 8. This prevents the food residue from being tightly wedged in the foramina, and thus, upon a subsequent step involving circulation of liquid, when the liquid passes down over member 8 to the drain opening 19, the food particles will be washed down and the screen openings cleansed.

At the end of the rinse operation, the water valve solenoid 31 will be deenergized, to shut off the provision of water, it being understood that this may be done earlier during the rinse cycle it a suflicient amount of water for the rinse cycle has already been provided. This, in effect, is a factor of the rate at which water is provided through inlet 23, and the precise instant of tie-energizing solenoid 31 (or whether it is energized once or several times) is not a prime factor for consideration in our invention. It will however be noted that the shutting off of the inlet flow of water, because of the high rate of recirculation, causes the amount of water being recirculated to decrease as Water passes down through the drain passage 19. This occurs at a fairly high rate even though only a small part of the recirculated liquid reaches the drain passage, the rest passing into receptacle '18 by the combined action of openings 22 and the pump 14; thus, the liquid used for the initial rinse is rapidly removed. Toward the end of the drain operation the motor 15 may be deenergized so that the last small amount of liquid passes down through openings 22 so as to completely empty the receptacle 18. During all this time, of course, the unit 26 continues to be provided in its condition (energized in the present case) whereby it causes removal of any matter passing down through passage 19.

After this first drain operation, the wash operation may be provided; this is somewhat longer than the first rinse operation (for instance, it may be on the order of six water.

minutes) but involves in similar fashion provision of a predetermined amount of water with recirculation of that In view of the fact that virtually all visible food particles have been removed during the first rinse, the unit 20 may be deenergized during the wash operation to close off the drain passage 19 and prevent the removal of liquid. This permits the initial charge provided for washing to be utilized without loss throughout the washing. It will, however, be understood that it is within our invention to provide again simultaneous operation of the pump motor 15 and the unit 29 if so desired.

The wash operation is then followed by two rinse and drain operations, as shown, with the last drain then being followed by the opening of switches 38, 39 and 4t) and the closing of switch 41 to provide a heat drying operation to dry the dishes. At the end of the heat drying operation, which may conventionally last on the order of twenty to thirty minutes, the operation of the motor 36 causes cams A and E to open switches 37 and 41 so that all of the switches are then opened with the result that the machine is de-energized and the dishwashing operation is terminated.

Referring now to the embodiment shown in FIGURE 4, parts which are the same as those shown in FIGURE 1 are indicated by the same numerals, and parts which are not shown are identical with those of FIGURE 1. The main difference in the structure of FIGURE 4 from that shown in FIGURE 1 is that instead of the bleed openings 22 of FIGURE 1, there is provided a siphon member 43 having its short leg 44 in receptacle 18 extending down to a point adjacent the bottom thereof and having its long leg 45 in drain passage 19. The siphon has its top portion 46 extending through the wall of passage 19 at a higher level than the maximum liquid level normally provided in receptacle 18, such liquid level being shown by the line L but at a lower level than the screen member 8.

In effect, instead of the openings 22 being used to get rid of the liquid in receptacle 18 at the end of any rinse or Wash operation, the siphon is caused to perform this function. The siphon is primed by stopping the operation of the motor 15 and therefore of the pump 14. When pump operation stops, all liquid eventually collects in receptacle 18 and this causes the liquid level therein to rise to level L which, although still below the level of the screen, is above the top 46 of the siphon member so that the siphon starts to operate and continues to operate until the water in the receptacle 18 has been substantially drained. It will be seen that this siphon readily replaces the openings 22 of FIGURE 1 as a means of getting rid of all liquid in receptacle 18 at the end of any particular operation, and that in other respects the structure and the correlation of operation of the components are the same as those discussed in connection with FIGURE 1.

Of course, with the structure of FIGURE 4, during an operation a charge of liquid may be added after motor 15 is deenergized so as to prime the siphon 43; this might possibly, for instance, be necessary as a result of the loss of liquid during the initial rinse operation as described in connection with the structure of FIGURES l, 2, and 3.

While, in accordance with the patent statutes, we have described what at present are considered to be the preferred embodiments of our invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and we therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A dishwasher comprising: a compartment for receiving dishes to be washed; liquid circulating means for forcibly circulating liquid into said compartment; a drain passage having an upper end communicating with the bottom of said compartment, said compartment having its bottom formed to slope downwardly from its edges to said drain passage; means controlling passage of solids and liquids down from said drain passage, said passage controlling means having first and second conditions re- 'spectively causing and preventing passage of solids and liquids; a liquid receptacle positioned below said compartment bottom about said drain passage, said compartment bottom having a portion formed as a foraminous member above said receptacle and about said drain passage; high floW capacity pumping means having an inlet connected to said receptacle adjacent the bottom thereof and having an outlet connected to said circulating means; means for providing liquid including an inlet passage having an upper end open to atmosphere and a lower end communicating directly with said receptacle, and an electrically controlled liquid inlet valve; low flow capacity means for voiding liquid from said receptacle into said drain passage; and sequence control means for controlling a dishwashing operation, said sequence control means controlling said passage controlling means, said pumping means, and said inlet valve; said sequence control means in the dishwashing operation providing an initial step in which said sequence control means causes opening of said inlet valve for a predetermined period and also provides said first condition of said passage controlling means simultaneously with operation of said pumping means.

2. The apparatus defined in claim 1 wherein said low flow capacity means for voiding liquid from said receptacle to said drain passage comprises openings in said drain passage adjacent the bottom of said receptacle and communicating therewith.

3. The apparatus defined in claim 1 wherein said low flow capacity means for voiding liquid from said receptacle to said drain passage comprises a siphon having a short leg extending down substantially to the bottom of said receptacle, a long leg extending down into said drain passage, and a top portion joining said legs, said receptacle being formed so that the liquid level therein is below the top of said siphon during operation of said circulating means and rises above the top of said siphon after said circulating means ceases to operate.

4. The apparatus defined in claim 1 wherein said passage controlling means comprises means for grinding up solids and pumping out liquids and solids when said passage controlling means is in its first condition.

5. A dishwasher comprising: a compartment for receiving dishes to be washed; liquid circulating means for forcibly circulating liquid into said compartment; a drain passage having an upper end communicating with the bottom of said compartment, said compartment having its bottom formed to slo e downwardly from its edges to said drain passage; means controlling passage of solids and liquids down from said drain passage, said passage controlling means having first and second conditions respectively causing and preventing passage of solids and liquids; a liquid receptacle positioned below said compartment bottom about said drain passage, said compartment bottom having a portion formed as a foraminous member above said receptacle and about said drain passage; high flow capacity pumping means having an inlet connected to said receptacle adjacent the bottom thereof and having an outlet connected to said circulating means; means for providing liquid including an inlet passage having an upper end open to atmosphere and a lower end communicating directly with said receptacle, and an electrically controlled liquid inlet valve; low flow capacity means for voiding liquid from said receptacle into said drain passage; and sequence control means for controlling a dishwashing operation, said sequence control means controlling said passage controling means, said pumping means, and said inlet valve; said sequence control means in a dishwashing operation providing an initial rinse step and subsequently thereto a washing step and additional rinse steps, said sequence control means in said initial rinse step causing opening of said inlet valve for a predetermined period and also providing said first condition of said passage controlling means simultaneously with operation of said pumping means, said sequence control means in said washing step and said additional rinse steps causing opening of said inlet valve for a predetermined period and causing operation of said pumping means alone during provision or said second condition of said passage controlling means for a period prior to provision of said first condition of said passage controlling means.

6. A dishwasher comprising: a compartment for receiving dishes to be washed; liquid circulating means for forcibly circulating liquid into said compartment; a drain passage having'an upper end communicating with the bottom of said compartment, said compartment having its bottom formed to slope downwardly from its edges to said drain passage; means controlling passage of solids and liquid down from said drain passage, said passage controlling means having first and second conditions respectively causing and preventing passage of solids and liquids; a liquid receptacle positioned below said compartment bottom about said drain passage, said compartment bottom having a portion formed as a foraminous member above said receptacle and about said drain passage; high flow capacity pumping means having an inlet connected to said receptacle adjacent the bottom thereof and having an outlet connected to said circulating means; means for providing liquid to said dishwasher including an electrically controlled liquid inlet valve; an air vent having a lower end communicating with said receptacle and an upper end communicating wtih atmosphere; low flow capacity means for voiding liquid from said receptacle into said drain passage; and sequence control means for controlling a dishwashing operation, said sequence control means controlling said passage controlling means, said pumping means, and said inlet valve; said sequence control means in the dishwashing operation providing an initial step in which said sequence control means causes opening or said inlet valve for a predetermined period and also provides said first condition of said passage controlling means simultaneously with operation of said pumping means.

References Cited in the file of this patent UNITED STATES PATENTS 2,620,811 Walker Dec. 9, 1952 2,829,348 Law Mar. 4, -8 2,867,224 Martiniak et al. Jan. 6, 1959 I 2,894,631 Levit et a1, July 14, 1959 

